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QUERYING DATA FROM A TABLE, QUERYING FROM MULTIPLE TABLES, USING SQL OPERATORS, MANAGING TABLES, USING SQL CONSTRAINTS, MODIFYING DATA
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SELECT c1, c FROM t INNER JOIN t2 ON condition; Inner join t1 and t SELECT c1, c FROM t LEFT JOIN t2 ON condition; Left join t1 and t SELECT c1, c FROM t FULL OUTER JOIN t2 ON condition; Perform full outer join SELECT c1, c FROM t CROSS JOIN t2; Produce a Cartesian product of rows in tables SELECT c1, c FROM t1 A INNER JOIN t2 B ON condition; Join t1 to itself using INNER JOIN clause SELECT c1, c FROM t RIGHT JOIN t2 ON condition; Right join t1 and t SELECT c1, c2 FROM t; Query data in columns c1, c2 from a table SELECT * FROM t; Query all rows and columns from a table SELECT c1, c2 FROM t WHERE condition; Query data and filter rows with a condition SELECT DISTINCT c1 FROM t WHERE condition; Query distinct rows from a table SELECT c1, aggregate(c2) FROM t GROUP BY c1; Group rows using an aggregate function SELECT c1, aggregate(c2) FROM t GROUP BY c HAVING condition; Filter groups using HAVING clause SELECT c1, c2 FROM t ORDER BY c1 ASC [DESC]; Sort the result set in ascending or descending order SELECT c1, c2 FROM t UNION [ALL] SELECT c1, c2 FROM t2; Combine rows from two queries SELECT c1, c2 FROM t INTERSECT SELECT c1, c2 FROM t2; Return the intersection of two queries SELECT c1, c2 FROM t MINUS SELECT c1, c2 FROM t2; Subtract a result set from another result set SELECT c1, c2 FROM t WHERE c1 [NOT] LIKE pattern; Query rows using pattern matching %, _ SELECT c1, c2 FROM t WHERE c1 [NOT] IN value_list; Query rows in a list SELECT c1, c2 FROM t WHERE c1 BETWEEN low AND high; Query rows between two values SELECT c1, c2 FROM t WHERE c1 IS [NOT] NULL; Check if values in a table is NULL or not
SELECT c1, c2 FROM t ORDER BY c LIMIT n OFFSET offset; Skip offset of rows and return the next n rows SELECT c1, c FROM t1, t2; Another way to perform cross join
CREATE TABLE t( c1 INT, c2 INT, c3 VARCHAR, PRIMARY KEY (c1,c2) ); Set c1 and c2 as a primary key CREATE TABLE t ( id INT PRIMARY KEY, name VARCHAR NOT NULL, price INT DEFAULT 0 ); Create a new table with three columns INSERT INTO t(column_list) VALUES(value_list); Insert one row into a table INSERT INTO t(column_list) VALUES (value_list), (value_list ), ….; Insert multiple rows into a table INSERT INTO t1(column_list) SELECT column_list FROM t2; Insert rows from t2 into t UPDATE t SET c1 = new_value, c2 = new_value WHERE condition; Update values in the column c1, c2 that match the condition DELETE FROM t; Delete all data in a table DELETE FROM t WHERE condition; Delete subset of rows in a table DROP TABLE t ; Delete the table from the database ALTER TABLE t ADD column; Add a new column to the table ALTER TABLE t DROP COLUMN c ; Drop column c from the table CREATE TABLE t1( c1 INT PRIMARY KEY, c2 INT, FOREIGN KEY (c2) REFERENCES t2(c2) ); Set c2 column as a foreign key CREATE TABLE t( c1 INT, c1 INT, UNIQUE(c2,c3) ); Make the values in c1 and c2 unique CREATE TABLE t( c1 INT, c2 INT, CHECK(c1> 0 AND c1 >= c2) ); Ensure c1 > 0 and values in c1 >= c CREATE TABLE t( c1 INT PRIMARY KEY, c2 VARCHAR NOT NULL ); Set values in c2 column not NULL TRUNCATE TABLE t; Remove all data in a table UPDATE t SET c1 = new_value; Update new value in the column c1 for all rows
ALTER TABLE t ADD constraint; Add a constraint Rename a table from t1 to t ALTER TABLE t DROP constraint; Drop a constraint ALTER TABLE t1 RENAME c1 TO c2 ; Rename column c1 to c